After a primitive supper in earthen bowls, we lay round the fire, listening to the talk of our men and the Indian women. It was mostly about adventures with wolves, and about the sulphur-workings, now discontinued. The weather had cleared, and as we lay we could see the stars shining in through the roof. About three in the morning I awoke, feeling bruised all over, as was natural after sleeping on a mat on the ground. Moreover, the fire had gone out, and it was horribly cold, as well it might be at 13,000 feet above the sea. I shook some one up to make up the fire, and went out into the open air. It was nearly full moon; but the moonlight was very different from what we can see in England, even on the clearest nights. On the plateau of Mexico, the rarity and dryness of the air are such that distant objects are seen far more distinctly than at the level of the sea, and the European traveller’s measurements of distance by the eye are always too small. The sunlight and moonlight, for the same reason, are more intense than at lower levels. Here, at about the same elevation as the top of the Jungfrau, the effect was far more striking, and I shall never forget the brilliant flood of light that illuminated that grand scene. Far down below I could see the plain, with houses and fields dimly visible. At the bottom of the slope began the dark pine-forest, which enveloped the mountains up to the level at which I stood, and there broke into an uneven line, with straggling patches running up a few hundred feet higher in sheltered crevices. Above the forest came a region of bare volcanic sand, and then began the snow. The highest peak no longer looked steep and pointed as from below, but seemed to rise from the darker line of sand in a gentle swelling curve up into the sky. There did not seem to be a speck or a wrinkle on this smooth snowy dome, the brilliant whiteness of which contrasted so wonderfully with the dark pine-forest below.